On Tuesday, the Food and Drug Administration (FDA) approved Qsymia, the second new diet drug in a month, and the most effective of the weight-loss pills that the agency has considered in recent years.

Qsymia, made by Vivus Inc., receives market approval on the heels of Arena’s Belviq (lorcaserin), the diet pill cleared by the FDA in late June. Before these two new drugs, the last prescription weight-loss pill to be green-lit by the government was Roche’s Xenical (orlistat) 13 years ago, in 1999.

Diet pills have had a spotty history with the FDA, largely because of safety problems involving the heart. Other drugs — most notably fenfluramine, used in the popular weight-loss combination fen-phen — have been withdrawn from the market for such hazards, and new drugs have had to clear a high bar for consideration.

The new pill, formerly known as Qnexa (the FDA asked Vivus to change the name to avoid confusion with another drug on the market), will be available by the fourth quarter of this year, according to the company’s president, Peter Tam. Here’s what you need to know.

Who can use Qsymia?
The drug is approved for obese adults with a body mass index, or BMI, of 30 or higher. It can also be used by overweight adults, with a BMI of 27 or higher, if they have at least one weight-related condition such as high blood pressure, Type 2 diabetes or high cholesterol.

How does it work?
Qsymia is a combination of two existing drugs: phentermine, an appetite-suppressing stimulant that has long been used for short-term weight loss, and topiramate, an anti-seizure medication used to treat epilepsy that makes people feel fuller after eating. Some doctors have already been prescribing the two drugs together for weight loss. Researchers say the key to Qsymia’s success is that it targets multiple brain pathways that trigger overeating.

How much weight will I lose?
It varies. In clinical trials, overweight and obese patients taking Qsymia for a year lost differing amounts of weight: on average, patients taking a middle dose of the drug lost 8.4% of their body weight; on a higher dose, patients lost 10.6%.

Most of the weight came off in the first three months, so doctors should monitor patients at that point to see if the drug is working. The FDA notes that people who don’t lose at least 3% of their body weight by three months are unlikely to go on to lose any significant weight, so they should either be counseled to discontinue the drug or to try a higher dose (Qsymia will be available in two doses). If patients still don’t lose at least 5% of their weight after three additional months on the higher dose, they should quit taking Qsymia.

The drug is designed to be used in conjunction with traditional weight-management strategies like diet and exercise. “This is not a magic pill. Patients can’t take it and think that’s all they have to do. It needs to be used with a lifestyle modification program,” W. Timothy Garvey, chair of the department of nutrition sciences at the University of Alabama-Birmingham, who studied Qsymia, toldUSA Today.

What if I just want to drop a few pounds?
Doctors stress that because of the potential risks of the drug, dieters should not use the drug for cosmetic weight loss. “It’s not for patients who want to lose a few pounds,” Tam toldUSA Today. Of course, concerns remain that once the drug is on the market, doctors can prescribe it to all comers. To prevent that, Qsymia will be available only by mail order at first, so that physicians can’t dispense it from their offices. It will also be available in specialized pharmacies that register for the right to sell the drug, where pharmacists have been educated about Qsymia’s risks and can pass that information along to patients and doctors.

What are the risks?
Potential heart problems and birth defects. In trials, some people taking Qsymia had an increased heart rate as well as a condition called metabolic acidosis, which can lead to hyperventilation, fatigue and anorexia. One of the ingredients in Qsymia, topiramate, has also been linked in previous studies to birth defects including cleft lip and cleft palate in women who take it during pregnancy.

Safety concerns led the FDA to reject Qsymia’s first bid for approval in 2010, but the agency and Vivus have now put in place strategies to reduce risk: for example, women of child-bearing age who want to take Qsymia must test negative for pregnancy before starting the drug and are expected to use contraception and take a pregnancy test once a month while on the drug. Worries remain, though: in a Vivus trial, 34 women on Qsymia became pregnant even though they were instructed to use contraception. (The company says no birth defects occurred.)

Patients’ heart rate should also be monitored regularly while taking Qsymia. People with recent or unstable heart disease or stroke are not recommended to take the drug because of the potential heart risks. Vivus has also agreed to continue monitoring Qsymia users for side effects after the drug reaches market; in particular, it will conduct a long-term cardiovascular outcomes trial to assess the effect of Qsymia on major events like heart attack and stroke.

Which is better, Qsymia or Belviq?
In clinical trials, people taking Qsymia lost more weight; those taking Belviq lost 5.8% of their body weight on average after a year. Based on the side effects profiles, however, some might consider Belviq to be less risky. “The majority of obese patients wanting to try drug therapy will end up seeing both drugs, regardless of which one they take first,” Simos Simeonidis, an analyst at Cowen & Company, told the New York Times, noting that he thought Qsymia would sell better.

Why is this approval important?
Because more than a third of American adults are obese — a proportion that’s growing — and there aren’t many effective weight-loss treatments out there to reverse the trend. Aside from diet and exercise or weight-loss surgery, patients have few options. The FDA’s approval of Qsymia, after such a long diet-drug drought and despite the potential safety problems that plague weight-loss pills, marks a willingness to make new solutions available.

How do you pronounce the name of this pill?
Qsymia is pronounced cue-SIM-ee-uh.

I started Qsymia in January, and I am now on the 11.25 dosage... starting on the 15 in a couple weeks. I'm fine, aside from the slight headache, but nothing WATER cannot cure. I've noticed my headaches come on only when I haven't had enough water. Other than that, I am fine. No suicidal thoughts. I have though, had sleepless nights, when i go up in the higher dose. but I'm not tired in the morning. I do have to force myself to eat. You have to have a good mindset to start the diet, stay positive, and have positive thoughts. I wish you all the best!

For those of you who say just eat healthy and exercise and you will lose weight you're wrong. It doesn't just work for everyone. I've done Chris Powells carb cycle program, gluten free diet, Weight Watchers a couple times and Arbonne cleanse program. I haven't lost weight. Over the past 4 years I've steadily gained 110 lbs. I'm now insulin resistant. I also potentially have hypothyroidism. Guess what else I have. A gym membership. And I use it. That is I use it when the horrible fatigue from my rheumatoid arthritis allows me the energy to exercise. Some of us do actually need help to try to lose weight to prevent further chronic illness. Vitamins and eating veggies doesn't cure RA and it doesn't automatically mean weight loss for everyone. Please be kind and remember not to judge someone else when you don't know their battle.

Dear Ronnieloo, My doc said its a life time commitment. That you don't stop it, only have your doc wean you off slowly. She knows I don't have any insurance and said it's very expensive. I was on Fen-Phen before and was a success. When they took it away, I was so mad. It was about a year before I started to gain again. Thank you to NESSA for the hint about prescribing the two drugs separately. John W. They never took the Phentermine away. It was the Phenfluramine that caused the health problems. I'm going to use WW first and if it isn't coming off she will prescribe but I have to stay on WW.

SERIOUS WARNING!My insurance doesn't cover qsymia so my doctor prescribed phentermine & topiramate which are covered. He also prescribed lorazepam for my anxiety. I have just been through a week in hell! I have has severe anxiety attacks, suicidal thoughts, rage, severe depression! And high ocular pressure in one eye, which I mistook for pink eye & could have left me blind! This combination of drugs almost killed me! The weight I lost is not worth my life, my sanity, or my vision!

Qsymia sounds like it is very potent, I prefer <a href="http://fat-loss-factor-exposed.blogspot.com/" target="_blank">diet and exercise</a>diet and exercise as a way to lose weight. However, I can see the appeal of a pill like this one. I just hope it doesn't hurt anyone.

Yea, seems FDA can be very picky about approving diet pills and seems they are absolutely right in doing so. Not everything can be approved because of health risks and I guess there's a fine line to be drawn between helping to lose weight and being a danger to ones heart.

Is Phentermine been actually approved by FDA? I've heard a lot of success stories but does it come with any side effects?

I used Phentermine for six months under the strict supervision of a doctor. But after weaning off, I find the withdrawals to be a horror. Migraines, EXTREME fatigue and I have gained 12lbs in two weeks and my diet and exercise has not changed at all.

There are some good pills that can be purchased over the counter heres a good list study.http://practicallist.com/diet-pillsBut I'm not sure how anything can suppress appetite, like the new prescription diet pills fha just approved. Basically most diet pills sold online are a sales page with a before and after picture; making unproven claims and feeding on peoples weakness to look good.

I am extremely suspicious of any drug as I always seem to react negatively to them and prefer natural alternatives. I am also very skeptical of diet pills but have recently thrown caution to the wind and purchased some albeit natural ones. I must say that having used suppress, satisfy and shed I am happy to announce that I have dropped from a size 14 to 12. My weight loss has not been incredible but it has been steady and all in all i am happy with it.

I am extremely suspicious of any drug as I always seem to react negatively to them and prefer natural alternatives. I am also very skeptical of diet pills but have recently thrown caution to the wind and purchased some albeit natural ones. I must say that having used suppress, satisfy and shed I am happy to announce that I have dropped from a size 14 to 12. My weight loss has not been incredible but it has been steady and all in all i am happy with it.

this can only work in combination with a carefully designed nutritional program, else you are going to fix the next set of problems. Then again.....why not just address the issues related to diet in the first place

The Standard American Diet has caused our cholesterol to increase as well as our weight, this increase has also caused us to have high blood pressure and increased blood sugar. The medical industry suggests we take statins to control our cholesterol, but they can cause diabetes by increasing our blood sugars, they also cause us muscle soreness and give us heartburn. So we take weight loss pills but they increase our blood pressure and give us insomnia. To offset that we take blood pressure medicine and a sleeping pill but a side effect is depression and impotence. Fortunately, the erectile dysfunction medicine and antidepressant relieve that issue but the antidepressant causes weight gain and gives us heartburn . We started taking an antacid but it gives us a headache and makes us moody. The fish oil should increase our good cholesterol so potentially we can stop taking the statin, but it gives us irregular heart beats. We would love to have a scotch but our liver’s are toxic and our kidneys are failing. So rather than commit suicide…

I get horrible migraines, the doctor put me on Topamax, guess what it does......makes you lose weight. In the month I have been on it I have lost 15 pounds. Also I have not had one migraine. I think I will stick to the Topamax. It does have the same side effects as this new drugs. Tingling in the hands and feet, altered taste, dry mouth. I drink a lot of water now, soda taste awful as does any carbonated drink. I am full after just a few bites of food. I also have changed my eating habits. I cut out the junk food and eat fruits instead of garbage. I feel 100% better and this is without any extra exercise. I will start walking this week. Now that I have lost the 15 pounds and the migraines are gone exercising will be easy.

Losing weight is not that difficult, you don’t need drugs to do it. Eat a lot of plants: beans, legumes, veggies, fruit, whole grains and avoid fat/oil at all costs. Not only has my weight dropped amp; sustained, my plaque is reversing less than a year after my quadruple bypass surgery. Here are my results showing plaque reversal in 8 months of a Plant Based diet: http://wholefed.org/2012/05/03... can pick apart how long humans have been eating meat or how or brains would be the size of peas without animal protein. There are thousands of studies and experts that will refute any effort that promotes focusing your diet on grains, vegetables amp; fruits.I say: try it. Try eating nothing but Plants amp; Grains for a week. Two weeks. One month. Don’t tell anyone, do it for yourself.There is no downside… only upside.Ian Welchwww.wholefed.org

I am shocked at the number of websites that are misspelling the name of this diet drug. Qsymia is a powerful medication with some subjects losing up to 10% of their body weight in a relatively short period. I commend you getting the spelling correct when it seems as if literally thousands of other websites are not using the correct brand name. http://qsymia.me

Took this medication combination, 6 years ago under the direction of the doctor who came up with the combo pill, Qsymia. It worked. Lost 125 pounds. They tell you however, it has to be taken for the rest of your life. Why? Because when you stop taking it, the weight gradually comes right back. Sooo....just eat right, excercise, excercise and more excercise. Everything in moderation. If you decide to take this pill get ready to drink tons of water and a wheelbarrow of vitamins. Otherwise you'll get kidney stones and your hair will fall out. And if you can not get your insurance to pick up the tab.........the toprimate was REALLY expensive. (The one ingredient in the combo) Hhhhmmm......I wonder how mush Qsymia is going to cost?